The risk of predation and intraspecific competition alter the seed dispersal behaviour by rodents; El perill de depredació i la competència intraespecífica alteren el comportament de dispersió de llavors per part de rosegadors

Rodents may play an important role as seed dispersers/predators in Mediterranean oak (Quercus spp) forests. There exists much information about the influence of seed size or composition on the rodent choices while the influence of other environmental factors (risk of predation, instraspecific competition) has been barely addressed. In a typical Mediterranean mixed oak forest we studied how the pattern of acorn dispersal/predation by wood mouse (Apodemus sylvaticus) was influenced by the risk of predation by genet (Genetta genetta) or intraspecific competition (wood mice presence) by means of simulating their odour clues. According to a sampling campaign the dominant species of rodent in the study area was wood mouse Apodemus sylvaticus. Mice responded to odour treatment because there was a significant delay in the handling of acorns in the genet treatment in comparison to the other two treatments. Concerning the distance of acorn dispersal, acorns from the mouse treatment were dispersed at shorter distances in comparison to the control treatment, while those from the genet treatment were dispersed at intermediate ones. This work shows a highly complex spatial pattern of acorn dispersal while it emphasizes the importance conserving the integrity of the food web structure because of the direct and indirect effects among different organisms at different levels.